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Square foot of heating surface

bean Member Posts: 34
How would I determine the Square foot of heating surface for a boiler?


  • Ironman
    Ironman Member Posts: 7,379
    It should be on the tag, but if it's hot water, take the net output and divide it by 150. For steam, by 240.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    EBEBRATT-Ed Member Posts: 15,619
    edited April 2019
    What @Ironman said is sq foot of steam or water. Heating surface of the boiler is a whole nother story

    That would be the exposed area of the boiler steel or cast iron exposed to the products of combustion that have water on the other side.

    This is an old rating seldom used except on steel boilers. If it's an existing boiler it would be on the tag.

    Scotch marine steel boilers are usually rated @5 square feet of heating surface /boiler hp. Old HRT boilers were 10 sq ft/boiler hp.

    pretty near impossible to determine if not on the tag or if mfg is extinct